Circuit breaker case structure

ABSTRACT

An electromagnetic circuit breaker for opening a set of contacts upon the occurrence of predetermined conditions, having an outer tubular casing closed at one end, but for a hole through which an operating handle extends, and a terminal-carrying baseplate closing the other end of the tubular casing. The operating mechanism of the circuit breaker is housed within an inner case formed by two interfitting case sections, the inner case having an opening through which the operating handle extends and a pair of openings through which extend the terminals carried by the baseplate. Also, a multipole circuit breaker may be formed by stacking, side-by-side, the inner cases, each having its own mechanism and each defining a pole of the multipole circuit breaker. The mechanisms of the multipole circuit breaker are interconnected so as to trip all poles thereof upon the tripping of any one pole, the multipole circuit breaker having a suitable larger outer casing and terminal carrying baseplate.

United States Patent [72] Inventors Ronald Nicol; 3,098,910 7/1963 Schwartz"; 335/9 Ralph B. Davis, Trenton, both of NJ. 3,141,082 1/1964 Hollyday 200/ I47 [21] P 16518 Primary Examiner-Harold Broome [22] Filed 1970 Attorney-Denny and Denny [45] Patented Dec. 7, 1971 [73] Assignee lleinemann Electric Company Trenton ABSTRACT: An electromagnetic circuit breaker for opening a set of contacts upon the occurrence of predetermined conditions, having an outer tubular casing closed at one end, but for [54] EE B E STRUCTURE a hole through which an operating handle extends, and a ter- 8 "wing minal-carrying baseplate closing the other end of the tubular [52] U.S.Cl 335/202, casing. The operating mechanism of the circuit breaker is 335/132 housed within an inner case formed by two interfitting case [5|] Int. Cl ..l-llh 13/10 sections, the inner case having an opening through which the [50] Field of Search 335/202, Operating handle extends and a pair of openings through 132,9; 200/168 A, 168 B, 168 C, 168 G, 147; which extend the terminals carried by the baseplate. Also, a

317/! I7 multipole circuit breaker may be formed by stacking, side-byside, the inner cases, each having its own mechanism and each keleilenws Cited defining a pole of the multipole circuit breaker. The

UNITED STATES PATENTS mechanisms of the multipole circuit breaker are intercon- 1,943,240 1/1934 Lear et al 335 202 as P Poles hereof "P ripping of any 2,903,782 /1959 Kiese] et 3L 335/9 one pole, the multipole circuit breaker having a suitable larger 3,052,778 9/1962 Kathe 335/202 Outercasing and terminal carrying baseplate- /z- 95 /7 7/ l 22 J I 72 23 58 J 7; /40 I I I PATENIEU DEC 7197:

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4 e Z W m PATENTED DEC 7 |97| SHEET 2 BF 5 CIRCUIT BREAKER CASE STRUCTURE BACKGROUND OF THE INVENTION This invention pertains generally to electric circuit breakers of the type having an electromagnetic tripping device and a linkage mechanism which includes an overcenter, automatically resettable toggle mechanism. More particularly, the in- ,vention concerns a novel outer housing and inner case structure for single-pole and multipole circuit breakers of this type.

BRIEF SUMMARY OF THE INVENTION It is an object of the invention to form a single-pole electromagnetic circuit breaker so that a major portion thereof may be easily incorporated as a subassembly of a multipole circuit breaker.

Another object of the invention is to provide a multipole circuit breaker in which each pole is composed of substantially the same inner case and the same internal operating mechanism as used in a single-pole breaker, the multipole unit being formed by placing single-pole units alongside each other and interconnecting their linkages.

The circuit breaker provided by this invention comprises an outer metallic housing and an inner case of electrical insulating material enclosed by the outer casing. A mechanism is disposed within the inner case and includes a movable contact engageable with a stationary contact. For tripping the mechanism upon predetermined electrical conditions to open the contacts, an electromagnetic device is provided. The outer housing includes a tubular casing and a baseplate which carries two terminals. One of the terminals is connected to the stationary contact and the other terminal is connected to the electromagnetic device.'The inner case is divided into two sections along a plane generally parallel to the path through which the movable contact moves during opening and closing of the contacts to jointly define a space within which the mechanism is received. The inner case sections have, at one end, wall portions interfitting with the terminals and the baseplate to restrain movement of the inner case sections relative to the baseplate after the outer tubular casing is placed over the inner cases and secured to the baseplate.

The foregoing and other objects of the invention, the principles of the invention and the best modes in which I have contemplated applying such principles will more fully appear from the following description and accompanying drawings in illustration thereof.

BRIEF DESCRIPTION OF THE VIEWS FIG. I is a perspective view of a completely assembled twopole circuit breaker incorporating this invention;

FIG. 2 is a perspective, enlarged view of the two-pole circuit breaker of FIG. I with the outer casing partially shown and cut away and displaced from the two inner cases, the mechanism of each pole being contained within each inner case and interconnected as shown; I

FIG. 3 is an enlarged perspective view of one of the two half cases which forms a part of one inner case;

FIG. 4 is a perspective view of the half case shown in FIG. 3 rotated 90 and showing the arc-suppressing grids of the circuit breaker in place;

FIG. 5 is an enlarged perspective view of the partially assembled two-pole circuit breaker, showing the circuit breaker mechanism placed upon the half case of FIGS. 3 and 4 and the baseplate assembled to the half case;

FIG. 6 is a front, enlarged perspective view of the other half case which together with the half case shown in'FIGS. 3, 4 and 5 forms an inner case for one of the poles, FIG. 6 also showing the inside of the half case.

' and 7 seated upon the interfitting with the half case shown in FIG. 5;

FIG. 9 is a fragmentary, greatly enlarged cross-sectional view taken along the lines 9-9 of FIG.8, showing the interfitting relation of the stationary contact, the half cases, and the baseplate, but omitting (for clarity) the mechanism and the arc grids within the inner case;

FIG. 10 is a greatly enlargedview taken along the line I0- 10 in FIG. 9, showing the openings through which the stems of the terminals extend and showing the stems in cross section;

FIG. 11 is a perspective view of an insulating spacer;

FIG. 12 is a perspective view illustrating the assembly shown in FIG. 11 after one half case of the second pole has been placed upon the first pole and the insulating spacer placed between them, 1

FIG. I3 is an enlarged side elevation showing a multipole breaker with a half case removed and the outer casing cut away to expose the operating mechanism with the contacts in the open position;

FIG. 14 is a cross-sectional view of an assembled two pole circuit breaker constructed according to this invention, the view being taken along the line I4 14 in FIG. I3, but omitting the arc grids;

FIG. 15 is a side elevation similar to FIG. I3, but showing the operating mechanism of the circuit breaker in the contacts closed position and parts of the frame and of the armature.

DETAILED DESCRIPTION Referring to the drawings, a multipole circuit breaker I0 is shown in FIGS. 1 to 16 comprising an outer housing or casing II enclosing two switch units or circuit breaker poles I2 and 13. The circuit breaker poles I2 and I3 comprise inner cases 14 and IS, the inner case 14 being divided into two juxtaposed, approximately half cases or sections I6 and I7, and the inner case 15 being similarly divided into two juxtaposed, approximately half cases or sections 18 and 19.

Only the pole 12 will be described in detail as the poles I2 and 13 are identical. However, where reference is made to the parts of the second pole I3, they will be identified with the same number corresponding to the parts of the first pole I2, but with a prime mark to distinguish the parts of the second pole.

The circuit breaker pole I2 includes an automatically resettable linkage mechanism 20 which is mounted within and enclosed by the inner case I4. A handle 21 is pivotally secured to the outer housing 11 and extends out of the housing II, as shown. The handle 21 has a forked lower portion 22, FIG. I3, which engages a bushing I07 centrally carried by a rod 95, the rod being in turn carried bylinks 23 and 23', respectively, of the mechanisms 20 and 20' of each pole I2 and I3.

The linkage mechanism 20, as shown in FIGS. I3, I4 and I5, further comprises a movable contact 30 carried by a movable arm 31 and engageable with a stationary contact 32, the latter being carried by a stem 33 forming part of a terminal 34. The movable arm 31 is connected by a flexible conductor 36 to one end of a coil 40 forming part of an electromagnetic device 41 which is also enclosed by the inner case 14 and which is associated with the linkage mechanism 20 to trip open the contacts 30 and 32 on predetermined overloads.

The link 23 is biased to the position of the handle 2I cor-' responding to the open-contacts position by a spring 37 coiled about the pin 45 which supports the link 23 and about which it pivots, one end 38 of the spring being biased against the pin 58 and the other end 39 being hooked around the frame plate 50. Upon tripping of the mechanism 20, as hereinafter described, the spring 37 resets the toggle assembly or latching mechanism 56.

The electrical circuit of the circuit breaker pole 12 is completed by connecting the other end of the coil 40 to a crimpable terminal section 42, the latter being carried by a stem 43 forming part of a terminal 44. The terminal section 42 may preferably be tilted at an angle to facilitate connecting it to the end of the coil 40, FIG. 5. As shown, the terminals 34 and 44 are carried by a baseplate 46 and extend outwardly therefrom 'on opposite sides thereofJThe baseplate '46 is preferably made of metal and has secured to it insulator sleeves 27 and 28 through which pass the contact terminals 34 and 44, respectively, and to which they are in turn secured.

The outer. housing 11 in addition to the baseplate 46 includes a tubular outer casing 35 (FIG. 2) having an end wall with an opening through which the handle 21 extends, and an opposite, open end which is closed by the baseplate 46. The inner cases 14 and have between them an insulating spacer 86 and an overall dimension such that they are received snugly within the four walls of the tubular casing 35. Preferably. the baseplate 46 and the tubular casing 35 are metallic, the baseplate 46 being soldered or brazed to the tubular casing 35, as shown in FIGS. 13, 14 and 15.

Further, the movable arm 31 is biased by a spring 47 toward the open position of the contacts 30 and 32 and the movable arm 31 is mounted on a pin 48 about which it pivots, the pin 48 being carried by two spaced plates 50 and 51 (FIG. 14) which are integral with an L-shaped member 52 (FIGS. 13 and 15) and jointly form a frame 53 for carrying the coil 40 and the mechanism 20. The end portions of pins 45 and 48 extend into holes 120 and 121, respectively, (FIGS. 4 and 6) formed in the opposed sidewalls 100 and 1 10 of the inner half cases 16 and 17, respectively, to locate the mechanism relative to the half cases.

The movable arm 31 is also connected by a pin 54 to a toggle assembly or latching mechanism 56, the latter being in turn connected to the handle link 23 by a pin 58. Upon tripping of the linkage mechanism 20, as hereinafter described, the spring 37 resets the toggle assembly 56.

The handle 21 pivots about a pin 60 having end portions carried by a threaded collar 62 which is suitably soldered to the outer tubular casing 35. A'suitable elastic seal 66 surrounds the handle 21 in the vicinity of the pin 60 within the collar 62 so as to provide with the solder joint between the baseplate 46 and the tubular outer casing 35 an hermetically sealed housing 11. An indicating tab is placed over the collar 62 and is secured to the collar by a threaded nut 26. The tab 25 may be used to correlate and indicate the closed and open positions of the contacts with the position of the handle 21.

The pin 54 connecting the movable arm 31 to the toggle assembly 56 has end portions which engage the plates 50 and 51 to limit opening movement of the arm 31, as shown in FIGS. 13 and 14.

The frame 53 forms part of the electromagnetic device 41 to which is secured a time delay tube 64 housing a springbiased magnetizable core (not illustrated) movable against the retarding action of a suitable fluid to provide a time delay before tripping of the mechanism at certain overloads.

The operation of this type of linkage mechanism 20 and electromagnetic device 41 is generally set forth in US Pat. No. 2,360,922, among others, but for clarity's sake may be briefly described as follows: when the handle 21 is moved counterclockwise from the position shown in FIG. 13 to that shown in FIG. 15, the toggle assembly 56 and the movable arm 31 all move down, against the bias of the spring 47, and move the contact into engagement with the stationary contact 32, achieving the closed position, illustrated in FIG. 15.

Upon the occurrence of a predetermined overload condition, assuming the circuit breaker to be in the contacts-closed Y position, the armature structure 70, which is also part of the electromagnetic device 41, has an attractable part 71 which is attracted toward. the pole piece 72 either after a time delay period or virtually instantaneously, depending on the overload current. The armature 70 is pivoted on a pin 77 whose end portions are also carried by suitable holes in the frame plates 50 and 51. The armature 70 also includes a balance portion 73 and a trip finger 74 and when the attracted part 71 of the armature 70 pivots toward the pole piece 72, the trip finger 74 pivots to the right and trips the arm 75 forming part of a latch assembly 76 which, when the toggle assembly 56 has been moved to the contacts-closed position, FIG. 15, is juxtaposed with the trip finger 74, whereupon the toggle mechanism 56 collapses and the contacts open under the pressure of the opening spring 47. In FIG. 15, part of the frame plate 50 and part of the armature balance portion 73 have been broken away for clarity.

To minimize and/or extinguish any are that may form between the contacts 30 and 32 whenever the contacts are opened, assuming the circuit to be energized, a stacked array of three magnetizable, U-shaped metal grids 78, 79 and 80 are supported within the two half cases 16 and 17, FIGS. 13 and 15. Each of the U-shaped grids 78, 79 and 80 has a leg which rests in notches or slots 82, 83 or 84, respectively, formed in a thickened portion of the half case 16, as seen in FIGS. 3, 4 and 9. The grids 78, 79 and 80 are prevented from escaping from the slots 82, 83 and 84, in the assembled breaker, by the sidewall 110 of half case 17, FIGS. 6 and 9, which is positioned over the grids and juxtaposed therewith. The grid 78 is received within the slot 82, FIGS. 3, 4 and 9, the right side of the slot 82, FIG. 9, being defined by the back wall 90 of the half case 16. The grid 78, therefore, abuts (or rests against) both the backwall 90 of the half case 16 and the corresponding backwall 91 of the half case 17.

The two poles 12 and 13 are also interconnected by a common trip rod 97, FIGS. 1, I3, 14 and 15, to trip the adjacent pole when one of the poles is tripped upon the occurrence of predetermined electrical conditions. The trip rod 97 has projections 98 and 99 (FIGS. 1,13, 14 and 15) engageable with associated mechanism 20 and projections 98' and 99' engageable with the associated mechanism 20 to rotate the rod 97 and trip the electromagnetic trip device of the pole adjacent to the overload pole. Referring to FIGS. 13 and 14 and the pole 12, the movable arm 31 and the balance portion 73 of the armature 70 are engageable with the projections 99 and 98, respectively, as shown, whereby when the movable arm 31 moves to the open-contacts position, the trip rod 97 is rotated and causes the armature of the adjacent pole to pivot in the direction to engage the associated latch for tripping the latter, as generally described in US. Pat. No. 3,0989 l 2.

A spring 132, FIGS. 2 and 16, biases the projections 98 and 99 away from the balance portion 73 of the armature 70 and toward the movable arm 31 when the movable contact is in the closed position, FIG. 15. The spring 132 has one end connected to the spacer 86 by being hooked thereto through the hole 149, FIG. 16, and the other end hooked to a projection 96 on the rod 97. When the contacts are closed, FIG. 15, the counterclockwise movement of the projection 98 away from the balance portion 73 is limited by the contact of the projection 96 on the rod 97 with the right-hand recessed surface forming part of the opening 145 in the spacer 86, FIG. 16. The projection 96 extends away from the rod 97 at approximately the same angle as does the projection 98 and the projection 96 is located such that when the rod 97 is in place in the assembled circuit breaker the projection 96 is midway between the pole housings and in the same plane as the spacer 86. Thus, the projection 96 is trapped between the inner cases 14 and 15 and thereby limits axial movement of the trip rod 97.

The half case 16, FIGS. 3, 4 and 5, in addition to the peripheral backwall through which the terminals 34 and 44 extend, includes an opposed peripheral front wall 102, opposite peripheral end wall 101 and 103, and a sidewall 100 from which the walls 90, 100, 101 and 103 project, as shown in FIGS. 3 and 4.

Similarly, the half case 17, in addition to the peripheral back wall 91, includes an opposed peripheral front wall 112, opposite peripheral end walls 111 and 113, and a sidewall from which the walls 91, 111, 112 and 113 project as shown in FIG. 6.

The back walls 90 and 91 of the half cases 16 and 17, respectively, each have mating surface portions which jointly form two approximately circular holes 135, FIG. 10, for receiving the stems 33 and 43 of the terminals 34 and 44, respectively, the terminals 34 and 44 being secured to and carried by the plate 46, FIGS. 9 and 15. The two half cases 16 and 17 mate together ina plane of jointure 81, FIG. 10, through the approximate middle of the housing formed by joining the two half cases. The plane of jointure 81 of the two half cases is approximately parallel to and extends through the plane through which the movable contact 30 moves.

The holes 135 are formed by the jointure of the openings 93 in end wall 91 of half case 17, FIG. and the openings 92 in end wall 90 of half case 16, FIG. 3. Referring to FIG. 7, the openings 93 of half case17, FIGS. 7 and 10, are of an extended semicircular shape and are defined by the approximately semicircular recesses Y87 and essentially rectangular shoulder projections 88, extending beyond the plane of jointure 81. Referring to FIG. 3, the openings 92 in end wall 90 of half case 16 are approximately L-shaped and are defined by the essentially flat surfaces 85, running substantially parallel to the plane of jointure 81 FIG.'10 but recessed therefrom, the portions 85 merging on one side into approximately quarter circular portions 89 which extend to the plane of jointure 81 to form part of the holes 135.

As seen in FIG. 3, end wall 101 of the half case 16 extends above one of the portions 85 to form a shoulder and with the corresponding portion 85 an L-shaped recess, see FIG. 10 also, for laterally aligning the walls 90 and 91 relative to each other. That is, with the half cases 16 and 17 abutting and interfitting each other, FIG 10, the leading surfaces of the projections 88 on wall 91 are juxtaposed with the flat portions 85 on wall 90 and a side surface of one of the right-hand projections 88 abuts the end wall 101 to prevent, in conjunction with other surfaces described hereinafter, lateral movement of one half case with respect to the other. As seen in FIG. 10, the wall 90 of the half case 16 does not extend beyond the plane of jointure 81 of the two half cases.

With further reference to FIG. 10, an opening 137 between the holes 135 in the half case is formed by mating U-shaped recesses in the end walls 90 and 91. The opening 137 may be used to accommodate part of an auxiliary switch (not shown) which may be carried by the baseplate 46 and which cooperates with the linkage mechanism to indicate the position of the movable arm 31 at a remote location.

The backwalls 90 and 91 of the abutting and interfitting half cases 16 and 17 are formed with circular depressions 139, FIGS. 3, 7, 9 and 10 surrounding the openings 135, FIG. 10. The portions 140 immediately adjacent the depressions 139 are raised to form platforms engaging the plate 46, as best seen in FIG. 9. Similarly, the front walls 102 and 112 of the half cases 16 and 17 respectively, have flat raised bosses 142 and 143, FIGS. 3, 4, 6 and 8, for seating the assembled inner housing against the closed end of the tubular outer casing 11 when the housing is inserted therein.

The peripheral walls 101, 102 and 103 of the half case 16 have peripheral thinned portions 104 whose upper surfaces, FIG. 3, define the peripheral plane of jointure 81 with the half case 17, the half case 16 also having recessed portions 105 coextensive with the peripheral portions 104, the recessed portions 105 being formed to receive mating projecting portions 114 of the half case 17, FIG. 6, in interfitting L-shaped relation therewith. The wall portions 114 of the half case 17, FIG. 6, interfit in an L-shaped manner with the recessed portions 105 of the half case 16 while the projecting portions 104 of the half case 16, FIG. 3, likewise interfit with the recessed portions 115 of the half case 17.

To accommodate the handle shaft 95, the front wall 102 and the sidewall 100 of the half case 16 and the front wall 112 and the sidewall 110 of the half case 17 are formed with mating slots 106 and 116, respectively, FIGS. 3, 4 and 6, through which the shaft 95 extends, as shown in FIG. 2.

To facilitate manual opening and closing of the contacts, the shaft 95 carries a bushing 107 at its midsection, the bushing 107 being freely rotatable on the shaft and engaged by the forked end portion 22 of the handle 21.

To accommodate the common trip rod 97, the sidewall and the end wall 103 of half case 16, FIG. 4, are formed with a slot 130, and the sidewall and end wall 113 of the half case 17, FIG. 6, are formed with a similar slot 131 which mates with the slot 130 to jointly define a semicircular, elongated opening through which the common trip rod 97 may extend to interconnect the poles 12 and 13, as shown in FIG. 2.

The slot 131, FIG. 6, is partially formed by a semicircular wall in the sidewall 110 of the half case 17. Likewise, the slot 130, FIG. 4, is partially formed by a similar semicircular wall 126 in the sidewall 100 of the half case 16, the semicircular walls 125 and 126 together forming bearing supports for the rod 97. The spring 132 also biases the rod 97 against the semicircular walls 125 and 126. To permit the projections 98 and 99 on the rod 97 to pass into the inner case after the spacer 86 has been placed between the assembled poles 12 and 13, the slots 130 and 131 include L-shaped notches 127 (FIG. 4) and 128 (FIG. 6) in the end walls 103 and 113, respectively, to together form a U-shaped recess.

FIGS. 2, 5, 8, 9, 11 and 12 illustrate the method for assembling a two-pole circuit breaker constructed in accordance with this invention. The are grids 78, 79 and 80 are first arranged inside the half case 16 as shown in FIG. 4. Next, the plate 46 is moved toward the half case 16 with the crimpable terminal section 42 extending at an angle upwardly away from the half case 16, as shown in FIG. 5, with the section 42 aligned with the side of the operating mechanism having the coil 40 so that the stationary contact 32 is aligned for placement within the arc grid 78. Since the stationary contact 32 is to trap and overhang the backwalls 90 and 91, placement of the stationary contact 32 within the arc grid 78 may be accomplished only by positioning the plate 46 against the wall 90 with the stems 33 and 43 overhanging the flat surfaces 85, i.e., with the contact 32 and terminal section 42 being both displaced a small distance to the right, as viewed in FIG. 10, at

this time temporarily overhanging the recessed walls 85. Then, by sliding the plate 46 toward the arc grid 78, the stationary contact 32 will move into place overhanging the quarter circle wall 89, as shown in FIG. 9, as the terminal section 42 also moves into place overhanging the quarter circle wall 89.

The mechanism 20 is then placed on the half case 16 and the end wire of the coil 40 is soldered to the terminal section Next, the half case 17 is assembled to the half case 16 by holding it above the mechanism 20 and above the arc grids 78, 79 and 80. The half case 17 held with its backwall 91 in abutment with the plate 46 but under the terminals 34 and 44' of the second pole. At such time the sidewall 100 of half case 17 may just contact the lower edge portion of the contact 32' and the terminal section 42'. The half case 17 is then lowered onto the half case 16 such that the projections 88 on half case 17 fit into the approximately L-shaped openings 92 in the half case 16 with the right-hand projection 88 abutting the sidewall 101 of halfcase 16, FIG. 10.

Further, the peripheral projections 114 and recesses 115 on half case 17 are aligned and mated with the corresponding projections 104 and recesses 105 on half case 16 to form an L- shaped interfit. This L-shaped interfit and the abutment of end wall 101 with one of the right-hand (FIG. 10) projections 88 join together to prevent lateral movement of the half cases 16 and 17 with respect to each other. With the half cases 16 and 17 thus in place, the stems 33 and 43 are enclosed in the holes 135 and parts of the walls 90 and 91 are trapped between the contacts 32 and 42 and the plate 46, the plate 46 being secured in abutment with the inner case 14 formed by the two half cases 16 and 17. The extent to which the backwalls 90 and 91 are trapped between the contact 32 and the terminal section 42 is indicated by the dotted line illustration of the contact 32 and the terminal section 42 in FIG. 10.

The half case 18 is then placed on the half case 17 so as to engage the terminals 34'and 44'. The spacer 86 is then placed between the half cases 17 and 18, raising the half case 18 into locking position between the contact 32' and the section 42', on the one side, and the plate 46 on the other side. The spacer has four raised dimples or dents 150, FIG. 11, located near the four corners of the spacer, a small distance inside the periphery of the spacer and suitably spaced to provide a base of support for the half case 18. The dimples 150 on the spacer 86 facilitate the positioning of the succeeding half case 18 into engagement with terminals 34' and 44' of the second pole, as described hereinafter. The dimples 150 also serve as compensators when an accumulation of dimension tolerances causes the overall inside dimension to exceed the inside dimension of the outer casing 11, because the dimples 150 can be compressed to reduce the overall width dimension of a multipole circuit breaker unit. I I

The spacer 86 has a cutout opening 145, FIG. 11, at one of its margins aligned with slots 130 and 131 on the half cases 16 and 17 through which the rod 97 passes to interconnect the tripping mechanisms of each of the poles of the circuit breaker. Likewise, the spacer has an opening 146 at another of its margins aligned with the opening 106 in the half cases 16 and 17 to accommodate the interconnecting shaft 95 which extends between handle links 23 and 23'. Further, additional openings 147 and 148 may be provided to assure proper seating of the spacer. The spacer 86 may be made of a variety of insulating materials.

The spacer 86 has a hole 149, FIGS. 11 and 16, located between the opening 145 and one of the dimples 150. In assembling the circuit breaker, the spacer 86 is placed on the half case 17 so that the raised portions of the dimples I50 extend away from the half case 17 and the hole 149 in the spacer 86 is intermediate the stationary contact 32 and the slots 130 and 131 in the half cases, FIG. 11.

The next step in the assembly of the two-pole circuit breaker is to couple the inner case of the second pole 13, consisting of half cases 18 and 19, to the second set of terminals 34 and 44' on the plate 46.

The are grids 78', 79 and 80' of the second pole 13 are first placed on the half case 18 and then the half case 18 is placed on the half case 17. The spacer 86 is then slid between the half cases 17 and 18 raising the half case 18 toward the terminals 34' and 44'.

One end of the coil (not shown) of the second pole 13 is soldered to the crimpable terminal section 42', as for the first pole 12. Next, the half case 19 is placed on top of the half case 18 in a manner similar to the placement of the half case 17 on the half case 16.

The shaft 95 is then placed through the holes in the handle links 23 and 23 and the trip rod 97 with its cam projections inserted into the mating slots 130 and 131 provided in the walls of the half cases, FIG. 2. The openings I45 and 146 in the spacer 86 now permit the spacer to be moved out sufficiently for one end of the bias spring 132 to be hooked or attached to the spacer 86 at the hole 149, the other end of the spring 132 having been first hooked or attached around the projection 96 on the rod.

The outer tubular casing 35, partially shown in FIG. 2, is then slid over the inner cases and the fork portion 22 of the handle 21 is moved to engage the bushing 107. The cover 11 is then crimped and solder-sealed or brazed to the plate 46 to complete the assembly, FIGS. 13, 14 and 15.

FIG. 17 shows a single-pole embodiment of a circuit breaker according to the invention. The component parts of the single-pole embodiment are the same as those of the double-pole circuit breaker described above. In the single-pole embodiment, the operating mechanism is housed with half cases 156 and 157 which are similar to the half cases 16 and 17, respectively, describe hereinbefore. The outer casing 151 is similar in shape to the tubular casing 35, but is of a smaller size, since the width to be enclosed is about half of a two-pole unit. The plate 158 is similar to the plate 46 previously described, however, it carries only one set of terminals centered on the plate 158 and is correspondingly narrower. The

common trip rod 97, used to interconnect the trip mechanism in the two-pole embodiment, is, of course, not needed in the single-pole embodiment. The shaft for the handle of the single-pole embodiment, corresponding to the shaft of the two-pole circuit breaker, FIG. 16, is shorter in length, since it only spans one link instead of two links.

In the assembly of the single-pole embodiment of FIG. 17, the linkage mechanism together with its electromagnetic device and the arc grids are arranged in the half case 156 in a manner similar to that described previously with reference to the two-pole breaker. The plate 158 is then coupled to the half case 156 by inserting the stationary contact carried by the plate 158 within the arc grids and aligning the crimpable terminal section with one end of the coil, as described with respect to the two-pole embodiment, but not shown in connection with the single-pole embodiment. The coil is then crimped and soldered to the crimpable terminal section carried by the plate 158. The other half case 157 is then lowered onto the half case 156. The shaft associated with the handle 155 is then inserted through the hole in the handle link.

To complete the assembly, the inner case consisting of the so assembled half cases 156 and 157 is then inserted into the outer housing 151', and the lower, fork portion of the handle 151 is moved to engage the associated shaft. The outer casing 151 is crimped and soldered to the plate 158, as described previously with reference to the two-pole circuit breaker.

While the invention has been described with reference to a single-pole and a double-pole circuit breaker, it can be seen that a circuit breaker with a large number of poles can be assembled using the principles of this invention. Such a mul tipole breaker would require only a larger terminal plate 46 and outer tubular casing 35, a longer (handle) shaft and a longer trip rod, in addition to the required number of linkage mechanisms, electromagnetic devices and inner casings for each pole.

Although the outer casing and the baseplate are preferably metallic, several other type of materials can be used, including insulating materials such as plastic materials.

While each inner case has been described in terms of half cases it will be understood that the inner case could be formed by sections which are not half cases without departing from the scope of this invention.

Having described the invention, we claim:

1. A circuit breaker comprising an outer housing,

an inner case of electrical insulating material enclosed by said outer housing,

a stationary contact within said innercase,

a mechanism within said inner case and including a movable contact engageable with said stationary contact,

an electromagnetic device for tripping said mechanism upon predetermined electrical conditions to open the contacts, I

a handle extending through said outer housing and into engagement with said mechanism,

a baseplate forming one end of said outer housing, and two terminals carried by said baseplate,

one of said terminals being connected to said stationary contact and the other terminal being connected to said electromagnetic device, and

said inner case being divided longitudinally into two sections along a plane generally parallel to the plane in which said movable contact travels to jointly define a space within which said mechanism is received.

2. The structure recited in claim I wherein said sections of said inner case are formed with interfitting wall portions.

3. The structure recited in claim 1 wherein said sections of said inner case are formed with at least one wall portion trapped between said stationary contact and said baseplate.

4. The structure recited in claim 3 wherein the terminal which is connected to said electromagnetic device has a lateral projection and said sections of said inner case are formed with at least one wall portion trapped between said lateral projection and said baseplate.

5. The structure recited in claim 4 wherein said handle extends through said outer housing and into said inner case at one end of said inner case and said terminals extend through said baseplate at the opposite end.

6. The structure recited in claim 1 wherein each terminal in cludes an enlarged portion within said inner case and a stem extending through said baseplate,

the inner case sections having wall portions trapped between the enlarged portion of each terminal and said baseplate to thereby restrain relative movement of the inner case sections relative to said baseplate, and

said wall portions jointly surrounding said stems.

7. The structure recited in claim 6 wherein one inner case section has slots,

are grids received within said slots,

the inner case section with said are grid slots having its wall portion recessed and the other inner case section having its wall portion projecting and mating with said recessed wall portion,

the recessed wall portion facilitating assembly of said baseplate to the inner case having said arc grids by providing said terminals with ready, lateral access to the interior of the inner case without disturbing said are grids during assembly of the circuit breaker.

8. The structure recited in claim 7 wherein said outer casing and baseplate are metallic and brazed to each other.

9. A circuit breaker comprising an outer housing,

an inner case of electrical insulating material enclosed by said outer housing,

a stationary contact within said inner case,

a mechanism within said case and including a movable contact engageable with said stationary contact,

an electromagnetic device for tripping said mechanism upon predetermined electrical conditions to open the contacts,

a handle carried by said outer housing and extending into said inner case for operating said mechanism,

said outer housing comprising a tubular casing open at one end and closed at the other end but for a hole through which said handle extends, and

a baseplate closing the open end of said tubular casing,

two terminals carried by said baseplate,

one of said terminals being connected to said stationary contact and the other terminal being connected to said electromagnetic device,

said inner case being divided into two sections along a plane generally parallel to the path through which said movable contact moves during opening and closing of said contacts to jointly define a space within which said mechanism is received,

the inner case sections having, at one end, wall portions intcrfitting with said terminals and said baseplate to restrain movement of the inner case sections relative to said baseplate after said outer housing is placed over the inner cases and secured to said baseplate, and

said terminals being generally disposed along said plane.

10. A multipole circuit breaker comprising a plurality of similar circuit breakers each constructed as recited in claim 1 except that said outer housing is large enough to enclose all of the inner cases and said baseplate is large enough to carry all of said terminals.

11. A multipole circuit breaker comprising a plurality of similar circuit breaker units,

an outer housing enclosing said units,

each unit comprising an inner case of insulating material within said outer housing,

a stationary contact within said inner case,

a mechanism within said inner case and including a movable contact engageable with said stationary contact, an electromagnetic device for tripping said mechanism upon predetermined electrical conditions to open the contacts, a handle carried by said outer housing and extending into said inner case for operating said mechanism, said outer housing comprising a tubular casing open at one end and closed at the other end but for a hole through which said handle extends, and a baseplate closing the open end of said tubular casing, two terminals carried by said baseplate one of said terminals being connected to said stationary contact and the other terminal being connected to said electromagnetic device, said inner case being divided into two sections to jointly define a space within which said mechanism is received, the inner case sections having, at one end, wall portions interfitting with said terminals and said baseplate to restrain movement of the inner case sections relative to said baseplate after said outer housing is placed over thinner cases and secured to said baseplate, each inner case including an opening, and means extending through the openings in said inner cases for interconnecting said units, whereupon an overload in any one electromagnetic device of any one unit causes said means to trip the so interconnected unit. 12. In a circuit breaker including a mechanism, an electromagnetic device for tripping said mechanism, a pair of con- 7 tacts and terminals for connecting the circuit breaker to a circuit, the improvement comprising an outer metallic housing formed by a tubular casing closed at one end by a baseplate, and

an inner case of electrical insulating material enclosed by said outer housing,

said inner case being snugly received within said tubular casing,

said baseplate carrying two terminals,

said inner case being trapped to said baseplate as a subassembly having mating portions locking said baseplate to said inner case.

13. The combination recited in claim 12 wherein said inner case includes bosses seated against a wall of said tubular casing opposite said baseplate.

14. A multipole circuit breaker comprising at least two circuit breakers constructed in accordance with claim 12 wherein said outer metallic housing is large enough to receive the inner cases,

said baseplate is large enough to carry all of the terminals and close said tubular casing,

an electrical insulating spacer between the inner cases,

said spacer having compressible means thereon,

a common trip rod extending between the mechanisms and rotatable upon the tripping of one mechanism to trip the other mechanisms, and

a spring between the inner cases having one end hooked to said spacer and the other end hooked on said common trip rod and biasing said rod away from the tripping direction and against bearings formed in walls of the inner cases.

15. The structure recited in claim 14 and further including a projection extending from said trip rod limiting rotation of said trip rod by abutment with said spacer,

said projection being trapped between inner cases so as to also limit axial movement of said trip rod.

16. The structure recited in claim 15 wherein said spacer has slots in its marginsto permit said spacer to be moved out between the inner cases so as to hook said spring onto said spacer and then be moved back between the inner cases. 

1. A circuit breaker comprising an outer housing, an inner case of electrical insulating material enclosed by said outer housing, a stationary contact within said inner case, a mechanism within said inner case and including a movable contact engageable with said stationary contact, an electromagnetic device for tripping said mechanism upon predetermined electrical conditions to open the contacts, a handle extending through said outer housing and into engagement with said mechanism, a baseplate forming one end of said outer housing, and two terminals carried by said baseplate, one of said terminals being connected to said stationary contact and the other terminal being connected to said electromagnetic device, and said inner case being divided longitudinally into two sections along a plane generally parallel to the plane in which said movable contact travels to jointly define a space within which said mechanism is received.
 2. The structure recited in claim 1 wherein said sections of said inner case are formed with interfitting wall portions.
 3. The structure recited in claim 1 wherein said sections of said inner case are formed with at least one wall portion trapped between said stationary contact and said baseplate.
 4. The structure recited in claim 3 wherein the terminal which is connected to said electromagnetic device has a lateral projection and said sections of said inner case are formed with at least one wall portion trapped between said lateral projection and said baseplate.
 5. The structure recited in claim 4 wherein said handle extends through said outer housing and into said inner case at one end of said inner case and said terminals extend through said baseplate at the opposite end.
 6. The structure recited in claim 1 wherein each terminal includes an enlarged portion within said inner case and a stem extending through said baseplate, the inner case sections having wall portions trapped between the enlarged portion of each terminal and said baseplate to thereby restrain relative movement of the inner case sections relative to said baseplate, and said wall portions jointly surrounding said stems.
 7. The structure recited in claim 6 wherein one inner case section has slots, arc grids received within said slots, the inner case section with said arc grid slots having its wall portion recEssed and the other inner case section having its wall portion projecting and mating with said recessed wall portion, the recessed wall portion facilitating assembly of said baseplate to the inner case having said arc grids by providing said terminals with ready, lateral access to the interior of the inner case without disturbing said arc grids during assembly of the circuit breaker.
 8. The structure recited in claim 7 wherein said outer casing and baseplate are metallic and brazed to each other.
 9. A circuit breaker comprising an outer housing, an inner case of electrical insulating material enclosed by said outer housing, a stationary contact within said inner case, a mechanism within said inner case and including a movable contact engageable with said stationary contact, an electromagnetic device for tripping said mechanism upon predetermined electrical conditions to open the contacts, a handle carried by said outer housing and extending into said inner case for operating said mechanism, said outer housing comprising a tubular casing open at one end and closed at the other end but for a hole through which said handle extends, and a baseplate closing the open end of said tubular casing, two terminals carried by said baseplate, one of said terminals being connected to said stationary contact and the other terminal being connected to said electromagnetic device, said inner case being divided into two sections along a plane generally parallel to the path through which said movable contact moves during opening and closing of said contacts to jointly define a space within which said mechanism is received, the inner case sections having, at one end, wall portions interfitting with said terminals and said baseplate to restrain movement of the inner case sections relative to said baseplate after said outer housing is placed over the inner cases and secured to said baseplate, and said terminals being generally disposed along said plane.
 10. A multipole circuit breaker comprising a plurality of similar circuit breakers each constructed as recited in claim 1 except that said outer housing is large enough to enclose all of the inner cases and said baseplate is large enough to carry all of said terminals.
 11. A multipole circuit breaker comprising a plurality of similar circuit breaker units, an outer housing enclosing said units, each unit comprising an inner case of insulating material within said outer housing, a stationary contact within said inner case, a mechanism within said inner case and including a movable contact engageable with said stationary contact, an electromagnetic device for tripping said mechanism upon predetermined electrical conditions to open the contacts, a handle carried by said outer housing and extending into said inner case for operating said mechanism, said outer housing comprising a tubular casing open at one end and closed at the other end but for a hole through which said handle extends, and a baseplate closing the open end of said tubular casing, two terminals carried by said baseplate one of said terminals being connected to said stationary contact and the other terminal being connected to said electromagnetic device, said inner case being divided into two sections to jointly define a space within which said mechanism is received, the inner case sections having, at one end, wall portions interfitting with said terminals and said baseplate to restrain movement of the inner case sections relative to said baseplate after said outer housing is placed over the inner cases and secured to said baseplate, each inner case including an opening, and means extending through the openings in said inner cases for interconnecting said units, whereupon an overload in any one electromagnetic device of any one unit causes said means to trip the so interconnected unit.
 12. In a circuit breaker including a meChanism, an electromagnetic device for tripping said mechanism, a pair of contacts and terminals for connecting the circuit breaker to a circuit, the improvement comprising an outer metallic housing formed by a tubular casing closed at one end by a baseplate, and an inner case of electrical insulating material enclosed by said outer housing, said inner case being snugly received within said tubular casing, said baseplate carrying two terminals, said inner case being trapped to said baseplate as a subassembly having mating portions locking said baseplate to said inner case.
 13. The combination recited in claim 12 wherein said inner case includes bosses seated against a wall of said tubular casing opposite said baseplate.
 14. A multipole circuit breaker comprising at least two circuit breakers constructed in accordance with claim 12 wherein said outer metallic housing is large enough to receive the inner cases, said baseplate is large enough to carry all of the terminals and close said tubular casing, an electrical insulating spacer between the inner cases, said spacer having compressible means thereon, a common trip rod extending between the mechanisms and rotatable upon the tripping of one mechanism to trip the other mechanisms, and a spring between the inner cases having one end hooked to said spacer and the other end hooked on said common trip rod and biasing said rod away from the tripping direction and against bearings formed in walls of the inner cases.
 15. The structure recited in claim 14 and further including a projection extending from said trip rod limiting rotation of said trip rod by abutment with said spacer, said projection being trapped between inner cases so as to also limit axial movement of said trip rod.
 16. The structure recited in claim 15 wherein said spacer has slots in its margins to permit said spacer to be moved out between the inner cases so as to hook said spring onto said spacer and then be moved back between the inner cases. 